Basic Research
Copyright ©2008 The WJG Press and Baishideng. All rights reserved.
World J Gastroenterol. Jun 21, 2008; 14(23): 3693-3709
Published online Jun 21, 2008. doi: 10.3748/wjg.14.3693
Negundoside, an iridiod glycoside from leaves of Vitex negundo, protects human liver cells against calcium-mediated toxicity induced by carbon tetrachloride
Sheikh A Tasduq, Peerzada J Kaiser, Bishan D Gupta, Vijay K Gupta, Rakesh K Johri
Sheikh A Tasduq, Peerzada J Kaiser, Bishan D Gupta, Vijay K Gupta, Rakesh K Johri, Indian Institute of Integrative Medicine, CSIR, Jammu-Tawi-180001, Jammu and Kashmir, India
Author contributions: Tasduq SA designed the study, performed the experiments, analyzed the data, drafted the manuscript and contributed in use of new reagents/analytic tools; Kaiser PS was equally responsible as the first author for performing the experiments and helping in data setting, statistics, arrangement of figures and manuscript drafting; Gupta BD performed the chemistry experiments; Gupta VK worked on the data analysis, application of statistics and manuscript correction; Johri RK was the group leader and was responsible for checking the hypothesis of research study and final corrections of the manuscript and acquired funding for the study.
Correspondence to: Sheikh A Tasduq, PhD, Scientist, Experimental Toxicology Lab, Division of Pharmacology, Indian Institute of Integrative Medicine, CSIR, Canal Road, Jammu 180001, Jammu and Kashmir, India.
Telephone: +91-191-2569000-10
Fax: +91-191-2569333
Received: December 10, 2007
Revised: April 1, 2008
Accepted: April 8, 2008
Published online: June 21, 2008

AIM: To evaluate the protective effect of 2'-p-hydroxybenzoylmussaenosidic acid [negundoside (NG), against carbon tetrachloride (CCl4)-induced toxicity in HuH-7 cells.

METHODS: CCl4 is a well characterized hepatotoxin, and inducer of cytochrome P450 2E1 (CYP2E1)-mediated oxidative stress. In addition, lipid peroxidation and accumulation of intracellular calcium are important steps in the pathway involved in CCl4 toxicity. Liver cells (HuH-7) were treated with CCl4, and the mechanism of the cytoprotective effect of NG was assessed. Silymarin, a known hepatoprotective drug, was used as control.

RESULTS: NG protected HuH-7 cells against CCl4 toxicity and loss of viability without modulating CYP2E1 activity. Prevention of CCl4 toxicity was associated with a reduction in oxidative damage as reflected by decreased generation of reactive oxygen species (ROS), a decrease in lipid peroxidation and accumulation of intracellular Ca2+ levels and maintenance of intracellular glutathione homeostasis. Decreased mitochondrial membrane potential (MMP), induction of caspases mediated DNA fragmentation and cell cycle arrest, as a result of CCl4 treatment, were also blocked by NG. The protection afforded by NG seemed to be mediated by activation of cyclic adenosine monophosphate (cAMP) synthesis and inhibition of phospholipases (cPLA2).

CONCLUSION: NG exerts a protective effect on CYP2E1-dependent CCl4 toxicity via inhibition of lipid peroxidation, followed by an improved intracellular calcium homeostasis and inhibition of Ca2+-dependent proteases.

Keywords: Negundoside, Silymarin, HuH-7, Carbon tetrachloride, CYP 2E1, Oxidative stress, Calcium, Toxicity